The present invention is concerned with a structure for heat transfer tube for heat exchangers and the like, and with the apparatus and method for manufacturing the same.
Heat exchangers are commonly used for the purpose of transferring heat from the flowing liquid in an enclosure to another fluid flowing in an adjacent enclosure without intermixing the fluids. Heat exchangers are in common use in some applications of solar heating devices utilizing a fluid, such as a liquid flow of high heat absorbing capacity, circulating through a primary fluid flow circuit connected to the solar heat absorber, and where it is desired to transfer the heat from the heated fluid in the primary circuit to another fluid, such as ordinary water or air, circulating in a secondary fluid flow circuit. Heat exchangers also are commonly used in marine and in stationary industrial internal combustion engine installations for absorbing heat from the engine closed cooling system, and in nuclear reactors for cooling the reactor and for utilizing the heat generated by the reactor.
Heat exchangers are often complex devices with many welded or brazed fittings and connections, and they are subject to rapid deterioration, especially when one of the fluids has a corrosive action on the wall of the containing vessels, conduits, and junctions. Conventional heat exchangers are bulky, expensive to fabricate, subject to corrosion and prone to develop leaks.